Let-off mechanism



Nov. 6, 1928.

J. NORTHROP LET-OFF MECHANISM Filed Feb. 11, 1927 2 Sheets$heet 1 Nov. 6, 1928. 1,690,424

' J. NORTHROP LET-OFF MECHANISM Filed Feb. 11, 1927 2 Sheets-Sheet 2 Patented Nov. 6, 1928.

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r o s or es-P Hamster Application filed February 11, 1927. erlal no.1e7,so4

The present invention relates to an improvement in let-offs for looms.

The object of the inventions to reorganize and improve the construction of letofis,

5 and to this end lthe invention consists in the letoif hereinafter described and particularly defined in the claims.

'The illustrated embodiment of the inven "tion is described as iollows: The frame 1 of the loom carriesuthe various parts cmcluding the swords 1Q,.theulay 3, .the 'piunan' 4, the crankshaft 15, nto. yfLhegwarp beam 6 is supported on ike warp Jheam atbracket 7 secure'el to the rear of the? loom eframe. :ThlS warp beani fbracket carries 1 a vertical: bracket 8, which atfits up 'erlend islbraced :to'ethe frarnef-byuthe members 10, and .carries the whip roll "1-1 mounted 0n the .whip rollarm 12, carried 1); the I whip roll 13,1Which. "is pivotally supported in the bracket-8. so the nvhip' roll shaftwis attached .the ilet-off control arm 14:. roll spring 15kmbracing'th'e rod 16 ismo'unted atlits le fthand endto" slide in the supper-t1? andpwotally attached at its other end 18 to the whip r011 as control arnijl, and affords means .for yleldingly press ng against the controlarmflto sh ort the 'izvhi roll inproper position.

pp fi 'ltion thereon. This headigl8 is providcthwith slot 51:3vhich embraces the-pin lingi e arm 31 .o'fthe:be1l',c1'ank,leve1' 32: p011 The-tension of t springmay Joe adjusted the adjusting a'nd check nuts QO inethe 40 qfislniljmannenjThe whip roll control armv carries at its lower-end the bar i l whichfextends fromthe arm to the-front ofgtheiloom,

bein received at the front betweenrtheiforlrs 22h jthe guide hraeket 23. The bar 21. 1s

m pivot-ally attached at 24"t0 the lowir endLof' the W ip roll arm, and may be adjusteclgnp on this pivot toloccupy *clifl'erent positions with @espeet to the whip roll control arm 14. JThe roll arm is extendecl lower end of the whip he pivpt' polnt to -the leftf as Lto the. take-up roll 43'.

be acljustedwin angular position (with respect to the Whip roll fancl then by ctightening the nut the bar may be secured rigidly to ,the Whip roll control arm. Tothe front endof .(thehar 21 is'pivotally attach'etllthe 130(128, 1

which is ,bent back upon itself at its upper end to embrace a pin 3.0, which is secured in the arm 31 of' the pawl carrying bell-bji-ank leverSQ. The other arm 33 oflthe lbellcrank lever carries the pawl 5 34, .ivhich :is adapted to engage the ratchet wheel 35 secured upon 1 the lworm shaft 36, which extends diagonally downward from the front of lthemachineeto the .rear thereof, being supported in suitable bearings inthe bracketwl37 .at the front of the machine andlthe bracket-.38 atithe rear of the machine. Upon-the rear end of lthe uivo'rm shaft :is secured the norm. Z40, which engages vthe vorm Wheel 41 .on the .iwarp .lheam. Actuation of the ratchet wheelsby the paivl'turns the ewarpbea m toilet-01f or letback theivarp, which extends upwand from .thebeam over the whip roll 151 through the harnesses over the breast ,ifroll .42

"/Thc bell lcrank ipawl'rcarrying lever "32 which rotates the ;Worin"shaftislactuated hy rneans' ofcaconnection'with .the'ilayL 0 "enemy 'shaft v l is secured; the M11145 which projects foiivarcllyufrom the lay shaft .be-

yoncl .the front .oi'ithe .machine Where in bolt A61forms a pivotzforthe pawl vactuatingmod 47., which extencls, i1p.wai'd1yto the slidehead 48 at the upper end of the'roil. eThislheadg48 and thence wis ladjustablyI secured ,to the .rod .by iiieans oflthe nuts 50 which are .tln'eacletlflon ,the rod \and :holclvthelheacl 48 in adjusted ,posirod 47 will be ineffective tolactllate the'fbell crank. lever. But .ivhem the a control rod 28 is by the. actuating, ro'tl 47. 1 A,.S;p ing.5 1 P111 .ep-loyefl-mnormallyf tenrling to 9mm gth p raised, ..thei.bell,crank levercvvillibe actuated the control rod 28 may prevent such turning movement when it is depressed, that is wsay, when the whip roll occupies a higher position than normal.

The front end of he worm shaft is provided with a hand wheel 53 by which the operator standing at'the front of the, machine may turn the worm shaft by hand,

either inthe direction to let-off more warp by turning it to the right, as'viewed from therfront of the machine, orby lifting-the pawl by pressure upon its tail 54 by the thumb 'whilei tnrnin the wheel with the same hand to the left, as viewed from the front of :the machine.

Thegeneraloperation of the mechanism is notdis-similar to the operation of let-offs heretofore employed in the art. 'When the warp istoo tight,.it depresses the whip roll which thereby'causes the control rod 28 to be raised'so asto permit the actuation of the worm shaft by the lay to cause the latter to rotate the warp beam to let-off the warp.

When the Warprtension diminishes below a predetermined amount, the whip roll? willrise slightly andthe control rod 28 will be pulled downwardlyrso as to prevent returning movement of the: pawl, whereupon the feed of-the warp from the beamwill be suspended. 1 Fromtime to time the feed will besuspended in the operation of thelloom.

advantage over this'construction because it enables the operative to release the warp ten s1on and to re-apply itagain without going In weaving, when the operatorhas a pick out 'he is required in" constructions of letofi mechanism heretofore employed, to go to the rear of the loom and to loosen the warp by manual manipulation of the let-off, and also tighten it again after the pick outis.

completed. The present-invention is of great to the back of the machine:

' whip rolhas in-"prior positive let-off mechthermore, it has been foundin actnal prac-.

ticethat this let-off improves the quality of the cloth.

" is claimed is:

anism, wherein, upon each movement of the,

pawl to move the ratchet forward, the whip roll was oscillated in both directions. Fur- Having thus described the invention, what ing means, gearingaconnectedtherewith, a

"shaft connecting with the gearingxextcnding from the lower back partof the loom to the upper front partof the loom and adapted to 1. A let-01f mechanism for looms having; In combination, a loom frame, warp supportrier ,mounted. for rocking movement, a springfor' moving thegpawl carrier in one direction, a connection between the pawl carrier and lay for moving the pawl carrier in the opposite direction, a whip roll supported for inovementin resjjonseto variations in the tension of the warp. and means in combinatioma warp beam, actuating means therefor including gearing. a shaft connected witlrthe gearing mounted on the loom and GXtQIlClJDQ' from the rear of the loom to the front thereof and adapted to be rotated manually from the front [Of the front of the loom, a pawl carrier-mounted adjacent said ratchet, a pawl on the pawl arm secured to the whip roll, and an armextended from the control arm .to the forward part of the loom and connected with the pawl actuating'means for the shaft for controlling the actuation thereof.

3. A let-off for looms having, in combination, warp supporting means at the rear of the-loom, gearing connected therewith, a shaft for. actuating the gearing extending from the-rear to thefront of "the loom and adapted to be rotated manuallyfrom the front of the loom, ratchet and pawl mechanism at the front of thewloom provided with driving means for moving the pawl in actuating direction and a spring for retractingthe pawl to initial position, a whip roll,

and connections therebetween and the pawl to prevent the spring from retracting the pawl as'long as the warp tension is greater than a predetermined amount.

The present construction 1s of advantage because the let-off is operated to feed the warp 'without much improvement of the 4. A let-off for looms, comprising in combination, a warp beam, a shaft for rotating the warp beam and extending to the front of the loom and adapted to be operated manually from theqfront of; theloom, means for rotating said shaft from a going por tion of the loonr including a-ratchet. disposed at thefront of the loom, a pawl adapted to engage and rotate the ratchet,

the feeding of the warp by loom, a ratchet securedto said shaft at the ill) a pawl carrier mounted fol-rocking movement to actuate the pawl, means for rock ing the pawl carrier, E whlp roll supported for .movement in response to variations in the .itension of the war and connections' between. the, whip ro and the ratchet and pawl ;mechanism and operable to regulate thestrokepf the. pawl carrier in response to variationsin the osition of the whip roll under the tension 0 the warp.

5.1A. let-oil for looms, comprising in combination, a warp beam, a shaft fdr .I'Otfita ing the warp beam extending to the front of the loom and adapted to be rotated manually from the front of the loom, means for rotating said shaft from a going portion of the loom including ratchet and pawl mechanism having a pawl carrier mounted for rocking movement to advance the pawl in a direction to rotate the ratchet, and means for rocking said pawl carrier, means supported for movement in response to variations in the tension of the warp, and connections between said means and said ratchet andpawl mechanism and operable to regulate the stroke of the pawl carrier in response to i variations in the tension of the warp.

6. A let-off for looms having, in combination, a warp beam, a shaft for rotating said beam and extending from the beam to the front of the loom and adapted to be rotated manually from the front of the loom, ratchet and pawl mechanism for turning said shaft and mounted at the front of the loom so that the pawl can be held manually out of engagement with the ratchet during the manual rotation of said shaft, a whip roll mounted for movement in response to variations in the tension of the warp, and connections between the whip roll and the ratchet and pawl driving mechanism for controlling the operation of the latter by the position of the whip roll under the tension of the warp. I

In witness whereof I have signed my name to this specification.

JONAS NORTHROP. 

